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Neo4j学习笔记二【Neo4j Java Api的使用】

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为了循序渐进，本章节将使用最基本的Neo4j Java Api构造上一章节图一的数据结构。

搭建环境

建一普通的maven工程即可，这个就不多说了，Neo4j依赖版本如下，暂时只用到这一个依赖。

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<dependencies>
	<dependency>
    	<groupId>org.neo4j</groupId>
        <artifactId>neo4j</artifactId>
        <version>3.1.0-M03</version>
    </dependency>
</dependencies>

使用Java Api构造数据

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public static void main(String[] args){
    /**
     * 指定Neo4j存储路径
     */
    File file = new File("/opt/neo4j-community-3.0.3/data/databases/graph.db");
    GraphDatabaseService graphDB = new GraphDatabaseFactory().newEmbeddedDatabase(file);
    try(Transaction tx = graphDB.beginTx()){
        /**
         * 新增User节点
         * 每个节点设置name属性
         * 添加Lable以区分节点类型
         */
        Node user1 = graphDB.createNode();
        user1.setProperty("name", "John Johnson");
        user1.addLabel(MyLabels.USERS);
        Node user2 = graphDB.createNode();
        user2.setProperty("name", "Kate Smith");
        user2.addLabel(MyLabels.USERS);
        Node user3 = graphDB.createNode();
        user3.setProperty("name", "Jack Jeffries");
        user3.addLabel(MyLabels.USERS);
        /**
         * 为user1添加Friend关系
         * 注：Neo4j的关系是有向的箭头，正常来讲Friend关系应该是双向的，
         *    此处为了简单起见，将关系定义成单向的，不会影响后期的查询
         */
        user1.createRelationshipTo(user2,MyRelationshipTypes.IS_FRIEND_OF);
        user1.createRelationshipTo(user3,MyRelationshipTypes.IS_FRIEND_OF);
        /**
         * 新增Movie节点
         * 每个节点设置name属性
         * 添加Lable以区分节点类型
         */
        Node movie1 = graphDB.createNode();
        movie1.setProperty("name", "Fargo");
        movie1.addLabel(MyLabels.MOVIES);
        Node movie2 = graphDB.createNode();
        movie2.setProperty("name", "Alien");
        movie2.addLabel(MyLabels.MOVIES);
        Node movie3 = graphDB.createNode();
        movie3.setProperty("name", "Heat");
        movie3.addLabel(MyLabels.MOVIES);
        /**
         * 为User节点和Movie节点之间添加HAS_SEEN关系
         * HAS_SEEN关系设置stars属性
         */
        Relationship relationship1 = user1.createRelationshipTo(movie1, MyRelationshipTypes.HAS_SEEN);
        relationship1.setProperty("stars", 5);
        Relationship relationship2 = user2.createRelationshipTo(movie3, MyRelationshipTypes.HAS_SEEN);
        relationship2.setProperty("stars", 3);
        Relationship relationship6 = user2.createRelationshipTo(movie2, MyRelationshipTypes.HAS_SEEN);
        relationship6.setProperty("stars", 6);
        Relationship relationship3 = user3.createRelationshipTo(movie1, MyRelationshipTypes.HAS_SEEN);
        relationship3.setProperty("stars", 4);
        Relationship relationship4 = user3.createRelationshipTo(movie2, MyRelationshipTypes.HAS_SEEN);
        relationship4.setProperty("stars", 5);
        System.out.println("成功");
        tx.success();
    }
	
    //关闭数据库
    graphDB.shutdown();
}

以上示例用到的两个枚举类如下

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/**
 * Label类型枚举类
 */
public enum MyLabels implements Label{
    MOVIES,USERS
}
/**
 * 关系类型枚举类
 */
public enum MyRelationshipTypes implements RelationshipType {
    IS_FRIEND_OF,
    HAS_SEEN
}

至此，数据构建完毕，可以启动neo4j console查看结果，下一章将对构建的数据进行遍历。